When I came to find out about the OpenRA project I really loved how easily you can get your hands on it. For example the re-balancing of the engineers was all done by community members. Capturing a construction yard or other vital buildings was a predominant strategy a few years ago. Not walling in your deployed MCV meant you already lost the game which scared away new players. So the Generals style external capturing was implemented and used in the Red Alert mod. It turned the game in favor for more interesting late game battles. For the Tiberian Dawn mod instead the sabotaging where engineers damage the buildings and can only capture badly damaged ones known from RA95 was added to allow more fast pace games, but still avoid game breaking overpowered engineer cheese tactics after just a few minutes of gameplay. The best of it all: the balancing isn't set in stone. To revert back to an instant capture is just a matter of changing a text file. You can also add the rule changes to a map that you can upload at http://resource.openra.net/ to test it against other players who will automatically download your custom map when they join the multiplayer lobby.
All in all this is a huge contrast to https://cncnet.org/ which tries to preserve the original game with patches being contributed by very few skilled people who cartographed its byte code and http://redalertpp.org/ which also goes for a conservative approach, but also is very secretive and follows a closed invite-only development model. If all the projects had the very same goals and design principles, they would in turn be quite redundant, so I quite like how the community ecosystem evolved with everyone finding their niche.

Sorry, you can't. The original Dune 2000 uses Direct X 5.0 for rendering so you need something else to create screenshots. The http://www.openra.net/ Dune 2000 mod utilizes OpenGL for rendering, but I don't know if the Steam overlay works with it.